Oil burner



5 Sheets-Sheet l nooo G. N. ALBREE OIL BURNER Filed Aug. 4, 1951 .July14, 1936. l

' July 14, E936. G. N. ALBREE OIL BURNER 5 Sheets-Sheet 2 Filed Aug, 4,1951 Patented July 14;"

UNITED STATES PATENT GFFICE 11 Claims.

'I'his invention relates to oil burners and particularly to a type ofburner which is self-gasifying, and in which no mechanical motion orforced draft is utilized to produce a combustible mixture of air andgasifled oil.

The principal object of the invention is to provide a burner in whichthe cool oxygen bearing air currents are diverted from the gasifyingchamber thereof thereby maintaining a high uniform gasifying temperaturewithin the gasifying chamber.

A further object of the invention is to provide an oil burner of adesign which is adaptable readily to the construction of burners havinga wide range of heating capacity.

A further object of the invention is to provide a burner having elementswhich may be readily fabricated.

A further object of the invention is to provide a burner in which aportion of the air enters the combustion chambers from a speciallyconstructed air feeding chamber.

A further object of the invention is to provide a burner in which aportion of the gasifying chamber may be removed readily to facilitatecleaning of the carbon from the burner.

Other objects and features will more fully appear from the followingdescription in connection with the accompanying drawings, and will beparticularly pointed out in the claims.

It has heretofore been diiiicult to obtain satisfactory dependableoperation in an oil burner fwhich is self-vaporizing when burning oilsof a relatively low volatility. The successful operation of such aburner depends not only upon a satisfactory high gasifying' temperature,but depends to a great extent upon maintaining such temperature at aconstant degree. The present invention accomplishes this result in asimple but entirely satisfactory manner.

Briefly the burner consists of an annular base member which constitutesa foundation upon which the other elements of the burner are supported,and is itself supported in position Within a heater, stove or otherapparatus for utilizing heat. 'I'he base is generally channel shaped incross section being entirely closed at its lower end and open at itsupper extremity. At a point substantially centrally between the sides ofthe base member is located a gasifying chamber having relatively heavyWalls which act to absorb and retain the heat generated by the burner.The gasifying chamber extends upward into the channel shaped chamber ofthe base member, and divides this chamber into two smaller concentricannular chambers which receive gas from the gasifying chamber through aseries of conduits or ports and serve to distribute the gas evenlythroughout the circumference of the burner to the combustion chambers.The combustion chambers are 5 annular in shape being open at their upperextremity, and are formed by vertical perforate walls which rise fromthe upper edges of the distributing chambers. These chambers will bereferred to herein as combustion chambers although l0 it is within thesechambers also that mixing of the oil vapor and air takes place toprovide a properly combustible iiuid.

The inner and outer combustion chambers are of such diameter that anappreciable space exists 15 between them. This space is utilized as anair feeding chamber which is closed at its bottom end by the upper wallof the gasifying chamber, and is closed at its upper end by a speciallyconstructed cover plate. This cover plate is com- 2o posed of twosections, an inner ring shaped section which closes the upper end of theair feeding chamber, and a central section which covers the centralchamber of the burner which is formed by the inner face of the innermostvertical wall of the inner combustion chamber. The cover plate formingthe closure for these two chambers has therein a plurality of conduitscommunicating from the central chamber of the burner to the upper end ofthe air feeding chamber.

The necessary air to support combustion within the combustion chambersis supplied partly by that which penetrates the perforated outervertical wall of the outer combustion chamber and the inner verticalwall of the inner combustion chamber. The balance of the air which actsto support combustion enters the combustion chambers by way of the airfeeding chamber which in turn receives a supply of air through theconduits in the cover pate. sufficient air is fed 4 thereby to theburner without cooling the gasifying chamber since the cool air currentsare diverted from the surfaces of the gasifying chamber. Furthermore,the air supplied to the burner through the feeding chamber accumulatesconsiderable heat before it enters the combustion chambers. The air maybe fed also directly into the air feeding chamber through a plurality ofconduits leading from the outside through the combustion chambers.

In the drawings:

Fig. 1 is a vertical sectional view through a preferred embodiment ofthe invention.

Fig. 2 is a top plan view of the apparatus.

Fig. 3 is a partial vertical section of a modined form of the invention.

Fig. 4 is a partial sectional view of a further modification of theinvention.

Fig. 5 is a sectional view on line 5-5 Fig. 2.

Figs. 6 and 7 illustrate modifications of the construction of the basesection of the burner. it being understood that the upper section of theburner may be constructed similar to that shown in either Figs. 1, 3, or4.

Fig. 8 is a vertical section through a burner having the base sectionillustrated in Fig. 6.

The preferred embodiment of the invention herein illustrated isgenerally cylindrical in shape and disposed with its axis vertically.The burner may be, however, of any desired' shape consistent with thebroad principles of the invention. The burner may be supported in anysuitable manner. An eiilcient construction is illustrated in which thebase I or the burner is supported by resting upon the upper face oi.' anadjustable frame 2 which is in turn supported the desired distance fromthe oor or foundation of the heating apparatus by means of a pluralityof posts 3 which may be embedded in the foundation or fixed in a baseplate 4. Any number oi such posts may be employed, the use of three suchposts constituting a desirable construction, two of which are shown inthe drawings. The upper ends of the posts are received loosely inapertures E in the frame 2. The upper ends of the posts 3 are providedwith nuts 6 upon the upper face of which the frame 2 rests. By adjustingthe nuts 8 upon the posts the frame 2 may be leveled accurately. Theburner may now be removed and replaced for cleaning or other purposeswith the assurance that it will reassume its proper level position.

'Ihe base member l is annular in form and desirably is hollow andgenerally channel shaped in cross section being closed at its bottom andopen at its upper extremity. The base member is divided into a centralchamber 1 which is the chamber into which oil is fed and in which itbecomes gasifled, and an inner and outer chamber 8 and il whichcommunicate with the gasifying chamber l by means of conduits or portsill.

The base member may be divided into its various chambers in any suitablenner. One method is illustrated in Fig. l wherein the base i is providedwith a recess il into which the oil is fed by means of the feed pipe i2which is connected to a source of supply not shown. Above the recess ilis placed a hollow heat retaining ring iii which opens downwardly andcooperates with the recess ii to form a gasifying chamber 1. Theposition of the ring I3 automatically forms the chambers 8 and ii, theside walls I 4 of the base i and the walls of the hollow ringy i3constituting the side walls thereof. The ring i3 may be provided with avertical heat collecting fin i5. The manner in which the recess li isformed produces stepped inner walls to the flanges of the base memberand the member i3 rests on the steps thus formed.

'I'he chambers il and 9 receive the gas generated by the gasifyingchamber through the ports Ill and distribute the gas evenly throughoutthe burner from where it rises into the annular combustion chambers I6and |1 which are situated directly above the chambers 8 and 8 and areformed by vertical walls rising from the upper sides of the chambers 8and 9. The vertical Walls are perforated cylinders disposed with theiraxesl vertically. The cylinders I8 and i9 form the combustion chamber I8while the cylinders 2li and 2| form the combustion chamber I1. Thecombustion chambers I8 and |1 are open at their upper ends, the chamber4|1 opening through apertures 22 formed in a specially constructed 5cover plate to be described hereinafter.

The perforated cylinders I8 and 2| rest upon shoulders 23 formed in theside walls of the base I while the cylinders I8 and 20 rest uponshoulders 24 in the ring Il. 'I'he perforated cyl- 10 inders aredisposed desirably substantially concentrically, and are so proportionedrelatively to each other that a chamber 25 is formed between theadjacent walls I8 and. 20 oi' the combustion chambers. A central chamber26 is also formed l5 by the inner cylinder 2| which is open at its lowerend and closed by a cover plate 21 of special design. The plate 21 restsupon the upper ends of the cylinders i9, 20 and 2|, and is composed oftwo connected sections an inner hollow cir- 20 cular section 28 actingto close the upper end of the chamber 2G and having a chamber 29 thereinopening downwardly. The other section 30 of the plate 21 is ring shapedand serves to close the top of the chamber 25. The two sec- 25 tions 28and 30 are connected by means of conduit members 3| which have passagestherein communicating from the chamber 29 to the upper end of thechamber 25. 'Ihe spaced relation of the Sectio/ns 80 and 28 providesaccess to the 3 outside for the burning gas within the combustionchamber i1. By reason of the construction of the cover plate 21 havingthe conduit members 3| extending from its central section to its outersection, the opening above the combustion cham- 35 ber i1 is partiallycut oil? leaving the openings 22.

The operation of the burner is as follows. To start the action of theburner heat is supplied in any desired manner as for instance byigniting raw oil at some point adjacent to or within 40 the burner or bymeans of auxiliary apparatus. As the temperature of the burner reachesits normal value, the walls and the fin I5 of the gasifying chamberbecome heated and act to vaporize or gasify the oil which is fed to the45 chamber by means of a feed pipe I2. The gas thus generated passesthrough the conduits I to the distributing chambers 8 and 9 from whichpoint it rises into the combustion chambers I5 and i'i. At this pointthe air which passes 50 through the perforations in the vertical wallsof the combustion chambers mixes with the gas therein to provide a morevolatile mixture and to support combustion. As the mixture of gas andair becomes ignited it ascends to the top 55 of the combustion chambers,and into the air above to supply heat to the heating apparatus.

A portion of the air consumed in the combustion chamber it reaches thechamber through the perforations of the wall I8, while a. portion of 0the air consumed in the combustion chamber I1 is supplied by passingthrough the perforations in the wall 2| thereof. The remaining portionof the air supplied to both combustion chambers 65 is fed thereto fromthe closed chamber 25.

Air is supplied to the chamber 25 through the conduit members 3| whichconduct the air from the upper portion of the central chamber 26. Sincethe temperature of the surrounding walls 70 of the chamber 26 isrelatively high the air therein becomes heated and is further heated asit passes downwardly into the chamber 25. The air reaching thecombustion chambers through the air feeding chamber 25, is, therefore,considervwith the walls of the gasifying chamber.

a,o47,sos

.ably raised in temperature, and for this reason ing chamber 25 isclosed at its upper end by an.

annular cover plate 32 which rests upon the upper ends of the cylindersI9 and 20. The chamber 29 is closed at its upper end by means of acircular cover plate 33. Inthis embodiment of the invention air from theoutside enters the air feeding chamber 25 through one or more conduits34 which pass through the combustion chamber I6 and are supported inclosely fitting apertures in the cylinders I8 and I9. `Air is fed alsoto the air feeding chamber 25 by means of one or more conduits 35 whichpass through the combustion chamber I1 and are suppoted in apertures inthe cylinders 20 and 2l in a manner similar to that of the conduits 34.The conduits 34l and 35 are situated preferably adjacent the lower endsof the cylinders but may be located in a position to conduct air to thechamber 25 at any desired point.

It will be noted that in both forms of the device as above describedthat the cool air which is fed to the burner does not come into contactBy diverting thesek air currents from the chamber in the mannerdescribed. the cooling thereof due to the draft of the burner iseliminated. By proper-v ly proportioning the elements of the burner andarranging them in the relation above set forth, it is possible toconstruct a burner employing the principles of the invention of highefficiency and which will produce a temperature of the proper degreewithin the gasifying chamber to completely gasify the oil as it is fedto the chamber. It is also contemplatedto feed air to the chamber 25 bymeans of the conduits 34 and 35 in combination with a cover plate 21conducting air to the chamber 25 through its conduits 3i. Such' aconstruction is shown in Fig. 8 wherein the base i of the burner isformed with the inner and outer gas-distributing chambers 8 and 9 andthe intermediate gasifying chamber 1, and wherein the gas-distributingchambers 8 and 9 communicate with the inner and outer combustionchambers I1, I6 formed by the perforated cylinders i9, I9, 20 and 2i inthe same manner as illustrated in Figs. 1, 3 and 4. These perforatedcylinders also form the air-feeding chamber 25 between the combustionchambers. In this embodiment the air is fed to the air-feeding chamber25 both through the conduits 3I formed in a cover plate 21, which issimilar to the cover plate shown in Fig. 1 and through other conduits34, 35 extending through the perforated cylinders as illustrated in Fig.4.

It is a distinct advantage also to construct a burner as describedhaving a portion of the gasifying chamber removable. By such design thecleaning of the burner is greatly facilitated.A Not only is the cleaningof the ring I3 greatly simpliled by its removal, but the base I being ofrelatively simple construction may be cleaned also with a minimum ofeffort. The cylinders I8, I9, 20 and 2i must, of course, be removed tocarry on the cleansing operation. Their removal and replacement is,however, a very simple operation since they rest by gravity upon theshoulders provided therefor.

Due to the particular 'shape of the base member I and the ring I3', theymay be formed readily of malleable sheet material. This feature isexceedingly valuable in simplifying and reducing the. cost ofmanufacture, and furthermore permits the use of various alloys of ironand steel such as the chromium alloys which resist oxidization andmaintaining a normal rigidity at high temperatures. thereby preventingalltendency of the burner elements to warp out of shape.

Figs. 6 and 8 illustrate a method of modifying the construction of thebase portion of the burner to permit the use of gases such asilluminating gas or a natural gas. The structure of the burner issubstantially the same as has been -previously set forth'with theexception that a plurality of small ports 36 are drilled through thewalls of the gas chamber 1 at short intervals close to the bottom edgeof the cylinders I9 and 20. These ports 36 act to conduct the gas to thecombustion chambers I5 and I1. Ihis form of burner functions insubstantially the same manner as those previously described. The chamber1 acts as a preheating agent for the gas fed thereto by the feed pipe 31connnected to the source of supply.

The perforations 36 in the ring 1 do not interfere with the operation ofthe apparatus as an oil burner but permit its use interchangeably asanoil or gas burner.l A further advantage of this feature is that itpermits gas to be burned for a short period to raise the temperature ofthe burner preparatory to burning oil. Furthermore if either gas or oilis used as the main fuel supply, and such supply will fail, the burnermay be maintained in operation by using an auxiliary supply of eithergas or oil.

Fig. 1 illustrates a very desirable construction of the base portion ofthe burner in which the base is channel shaped in cross section havingno recess as in the burners previously described. The side walls of thebase member are provided at intervals with short vertical ribs 38 uponthe upper ends of which rest a specially shaped gasifying ring member39. The ring member 39 has a chamber therein opening downwardly, theside walls of which 'are bent laterally outward and rest upon the ribs38. The peripheral edges of the laterally bent portions of the ring 39 tloosely within the base member, and thereby provide space through whichthe gas generated within the gasifying chamber 40 may flow into the gasdistributing chambers 1 and 8. The design of this particular form of theburner lends itself to large scale production, and is very easilydisassembled and may be cleaned with a minimum of effort.

Another valuable feature of the invention is the adaptability of theburner to increased capacity by adding more combustion chambers. Theefficient character of the gasifying chamber permits a sufficientquantity of gas to be generated to supply the additional combustionchambers. One or more additional combustion chambers may be added to thecentral or main unit either outside or inside, or both inside andoutside of the main unit. A desirable construction to carry out thisfeature of the invention is illustrated in Fig. 3 showing one additionalcombustion chamber 4I outside of, concentric with and spaced from thechamber I6. The chamber 4I is similar to the other combustion chambers,and has a gas distributing chamber 42 at its lower end which is providedwith vertical perforated walls rising from the upper edges of thechamber 42 in the form or cylinders 4s and u which extend upward to thelevel of the other cylinders. The outermost-cylinder 43 is extended ashort distance beyond the other cylinders. By thus extending the outercylinder it has been found by experimentation that the outer ring offlame issuing from the burner is maintained symmetrical in form, andburns with a steady even heat which otherwise is not the case. 'I'henatural draft caused by the rising currents of air adjacent the outersurface of the outer cylinder 43 from the burner has a tendency to causethe outer ring of flame to burn unevenly. In each of the other formspreviously described, the outer cylinder is extended slightly above theinner cylinders to improve the function of the outer combustionchambers.

The gas distributing chamber 42 is supplied with gas from the chamber 9by means of a series of conduits 45, one of which is herein showncommunicating from the lower portion of the chamber 9 to the lowerportion of the chamber 42. To facilitate the construction of the basemember in this particular form of the device, the conduits 4E aredrilled through cylindrical sections 46 cast integral with the chambersil and 42. The sections 46, one of which is shown in the drawings, serveto support the outer combustion chamber from the main portion oi theburner. The conduit 45 may, of course. be formed by coring in the usualmanner or may be drilled after the casting process. To accomplish thedrilling process, an aperture 4l is drilled through the outer wall 43ofthe chamber42 in line with the sections 46. The drill used for thispurpose is then forced to penetrate the section 46 and enter the chamberd. Upon completion of the drilling operation the aperture 4l' is pluggedin any desired manner such as by means of the screw threaded plug 49.

The chamber 5U formed by the cylinders i 9 and M is open at its bottomend by reason of the space existing between the chambers 9 and d2, andis closed at its top by an annular cover plate lil. Air reaches thecombustion chamber 4i from the outside directly through the perforatedcylinder 43, and-also by entering the chamber 5&3 from below andpenetrates the cylinder it through the perforations therein. The otherelements of the burner function in the same manner as that already setforth.

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is:

1. An oil burner comprising an annular base member presenting inner andouter annular gas distributing chambers closed at their sides and bottomand open at their top, perforate walls extending upward from the sidesof said chambers to form annular combustion chambers above andcommunicating with said gas distributing chambers, a gasifying chamberinto which oil is fed situated between the gas distributing chambers,the side walls of the gasifying chamber forming the inner and outer sidewalls of the outer and inner annular gas-distributing chambers, conduitscommunicating from the gasifying chamber to the distributing chambers,an air feeding chamber between the combustion chambers closed at itsbottom and top and conduits acting to conduct air from outside thecombustion chambers to said air feeding chamber at points removed fromthe walls of the gasifying chamber whereby air will be conducted to theair feeding chamber without cooling the gasiiying chamber aoczsos andwill become preheated before entering the combustion chambers.

2. An oil burner comprising an annular base member presenting inner andouter annular gas distributing chambers closed at their sides and 5bottom and open at the.top, perforate walls extending upwardly from thesides of said chambers to form annular combustion chambers open at theirupper ends situated above and communicating with said gas distributingchambers. 1o the innermost perforate wall forming a central cylindricalchamber opening to the air, a gasifying chamber between the gasdistributing chambers and into which oil is fed, conduits communieatingfrom the gasifying chamber to the gas l5 distributing chambers, an airfeeding chamber between adjacent walls of the combustion chambers closedat its bottom and top and means to conduct air from the central chamberinto the upper end of said air feeding chamber.

3. An oil burner comprising an annular base member having a centralopening to the air and presenting annular concentric gas distributingchambers closed at their sides and bottom and open at the top, perforatewalls extending upwardly from the sides of said chambers to form annularcombustion chambers open at their upper ends, an air feeding chamberbetween the combustion chambers closed at its bottom and a central airchamber communicating with said central opening, a gasifying chambersituated between the gas distributing chambers into which the oil isfed, conduits communicating from the gasifying chamber to the gasdistributing chambers, a cover plate having two concentric sections withspace between, one section closing the top of said air feeding chamberand the other section closing the central opening of the burner, saidcover plate having conduits therein acting to conduct air from saidcentral opening to the top of said air feeding chamber in which chamberthe air is preheated and then passes through the perforations in thewalls thereof to mix with the gas in the combustion chambers.

d. An oil burner comprising an annular base member presenting inner andouter concentric gas distributing chambers closed at their sides andbottom and open at the top, perforate walls extending upwardly from thesides of said chambers to form annular combustion chambers open 50 attheir upper ends, a gasifying chamber situated between the gas feedingchambers and into which the oil is fed, conduits communicating from thegasifying chamber to the said gas distributing chambers, an air feedingchamber between adjacent walls of the combustion chambers closed at itstop and bottom, conduits for supplying air to said air feeding chamberfrom outside the combustion chambers, an additional combustion chamberdisposed concentrically of the base member and spaced therefrom andconduits connecting the gas distributing chambers with the additionalcombustion chambers.

5. An oil burner comprising an annular base member presenting inner andouter annular gas distributing chambers closed at their sides andbottom, perforate walls extending upward from the sides of said chambersto form annular combustion chambers, a gasifying chamber into which oilis fed situated between the gas distributing chambers, a plurality ofsmall conduits formed in the upper portion of the side walls of thegasifying chamber communicating from said gasifying chamber to the lowerend of said combustion chambers, an air feeding chamber between adjacentwalls of the gasifying chamber closed at its bottom and top ends andconduits acting to conduct air from outside the combustion chambers tothe air feeding chamber at a point removed from the walls of thegasifying chamber.

6. An oil burner comprising an annular base member presenting inner andouter annular gas distributing chambers closed at their sides and bottomand open at their top, perforate walls extending upwardly from the sidesof said chambers to form annular combustion chambers above andcommunicating with said gas distributing chambers, a gasifying chamberinto which oil is fed situated between the gas distributing chambers, aplurality of small conduits distributed throughout the periphery of thegasifying chamber at the upper portion thereof communicating therefromto the base of the combustion chambers, a plurality of conduits at thelower portion of the gasifying chamber communicating therefrom to thegas distributing chambers, an air feeding chamber between the combustionchambers closed at its bottom and top and conduits acting to conduct airfrom outside the combustion chambers to said air feeding chamber atpoints removed from the walls of the gasifying chamber whereby air willbe conducted to the air feeding chamber without cooling the gasifyingchamber and will become preheated before entering the combustionchambers.

"l. An oil burner comprising an annular base member channel shaped incross section opening upward and having an annular recess formed in thebottom wall thereof into which oil is fed, a hollow annulus channelshaped in cross section opening downward and positioned above saidrecess to form therewith a gasifying chamber and dividing the remainingspace within said basemember into inner and outer gas distributingchambers, combustion chambers situated above and communicating with saidgas distributing chambers, conduits communicating from the gasifyingchamber to the gas distributing chambers and means to feed air to saidcombustion chambers at points removed fromv the gasifying chamber.

8. A liquid fuel burner comprising, in combination: an annular basering; spaced shells, certain of which are perforated, extending abovesaid base ring and coacting therewith to define inner and outercombustion chambers, an air passage therebetween and an inner downwardlyopen air chamber; means for admitting air to Vsaid air passage; anannular inverted channel shaped member supported above said ring, belowand of the same radial extent as said air passage and forming with saidbase ring a vaporized fuel passage constituting the principal means fordistributing the vaporized fuel to said combustion chamber; means forsupporting said member; means comprising a portion of said ring belowsaid member for supplying fuel vapor to said fuel passage; saidvaporized fuel passage opening into said combustion chambers.

9. A liquid fuel burner comprising, in combination: an annular basering; shells, certain of which are perforated rising from said ringadjacent its inner and outer peripheries respectively; intermediatespaced shells; means supporting said last named shells aboveintermediate 5 portions of said base ring, and with said first namedshells and with each other dening inner and outer combustion chambersand an intermediate air passage; an annular ring supported above saidbase ring and the lower edges of said 10 intermediate shells, extendingcontinuously between said intermediate shells, forming a bottom` wallfor said air passage and an upper wall of an annular vaporized fuelpassage; said vaporized fuel passage forming the principal means l5 fordistributing the vaporized fuel to said combustion chambers; means toadmit air to said air passage; means to supply fuel vapor to saidvaporized fuel passage comprising a portion of said base ring, and meansfor supporting said annular 20 ring above said annular base ring; saidvaporized fuel passage opening into said combustion chambers.

10. An oil burner comprising an annular base member having upstandingoutery andinner con- 25 centric fianges provided with stepped walls, ahollow annulus channel-shaped in cross section opening downwardly andhaving its edges resting on the stepped portions of said outer and innerwalls, said annulus forming with the base mem- 30 ber an annulargasifying chamber and with the outer and inner walls of said basemember, an outer and an inner gas-distributing chamber, a separatecombustion chamber communicating with each gas-distributing chamber,conduits 35 forming communication between the gasifying chamber and eachgas-distributing chamber, means to feed air to the combustion chambersat points removed from the. gasifying chamber and means to supply liquidfuel to the gasifying chamber.

11. An cil burner comprising an annular base member having upstandingouter and inner concentric fianges and an annular recess in the bot-ltom wall thereof, an annular inverted channelshaped member situatedbetween said flanges and forming with said recess'an annular gasifyingchamber, said channel-shaped member also forming with said anges outerand inner concentric gas-distributing chambers, the walls of saidinverted channel-shaped member having openings through which gas isdelivered from the gasifying chamber to said gas-distributing chambers,a plurality of concentric perforated walls, one supported on the outerange, one on the inner ange, and 55 others on said invertedchannel-shaped member, said perforated walls forming inner and outercombustion chambers communicating with the inner and outergas-distributing chambers and also forming an air feeding chamber abovesaid 60 annular channel-shaped member and conduits to conduct air fromoutside the combustion chambers to said air feeding chamber.

GEORGE NORMAN ALBREE.

